What is Stargardt's Disease?
Stargardt's disease, also known as fundus flavimaculatus, is a recessive inherited disorder of the central nervous system that affects the retina of the eye, particularly the macula.
There are several different forms of Stargardt's disease. The most common form is STDG1.
People diagnosed with STDG1 will have a sudden, rapid loss in vision at a certain age in childhood, usually upon entering high school, that will eventually stabilize to about 20/200 vision quality.
A person with Stargardt's disease will have a buildup of lipofuscin (a chemical which is essentially vitamin A) in the retina, causing yellowish-white flecks to appear in the retina and the retina to begin looking like "beaten metal or bronze." This deposition of vitamin A in the retina will become toxic, causing the photoreceptor cells of the eye to die. This will cause the most distinguishing feature of Stargardt's disease, a loss in central vision over time. Other symptoms include a loss in visual sharpness and the ability to see some or many colors, exceptional difficulty in seeing at night at all, and distorted vision, especially near the around or in the central vision. Although many people with Stargardt's disease will often lose almost, if not all of their central vision, it is very rare that they will lose their peripheral vision.
At What Age is the Onset of the Disease?
The disease usually manifests itself in early childhood or adolescence, usually from around 6 years old at the earliest to 30 years old. A majority of people show symptoms of the disease and are diagnosed between the ages of 16 and 18. Despite this, there have been some rare cases of people diagnosed with Stargardt’s in their 70s or 80s.
What is the Expected Lifespan of a Person With This Disease?
The expected life span of a person with Stargardt’s disease is normal. The disease has no impact on the general health of a person. The only part of the body that is impacted are the photoreceptor cells in the retina of the eye.
What Do Doctors Use to Diagnose This Disease?
Stargardt’s disease is diagnosed by physicians by clinical characteristics, or characteristics that become evident about the patient when working with, treating, and testing the patient. Doctors may find evidence to think that a patient has Stargardt's disease from findings in fundus autofluorescence (FAF) imaging, confocal scanning laser ophthalmoscopy, (cSLO) optical coherence tomography, (OCT) and fluorescein angiography, (FA) all of which allows doctors to better examine a patient’s retina and observe if lipofuscin is being built up in the eye. The natural autofluorescent properties of lipofuscin have allowed these techniques to develop into safe, non-invasive ways of determining how lipofuscin (it’s major component is A2E) is distributed in the eye, a trait which will tell a doctor whether or not a patient has Stargardt’s disease. A deposition of lipofuscin in the retinas will indicate that something wrong is occurring and that the patient likely has Stargardt’s disease.
Within recent years some new ways of diagnosing patients have come about, including different kinds of novel retinal imaging methods and different types of genotyping (screening of gene mutations) such as the use of ABCA4 microarray and direct sequencing. The ABCA4 microarray is a grid of DNA segments that is used to test and map for problems with this gene. Direct sequencing is a process of determining the proper sequencing of nucleotides in DNA. By looking at the normal order of nucleotides, doctors can compare segments of a patients DNA with generally what it should be in order to determine what base pairs might have occurred incorrectly in the patients DNA.
Prevalence - Statistics
Stargardt Disease is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). A rare disease is categorized as one that affects 1 person per every 2,000. This means that Stargardt Disease, or a subtype of Stargardt Disease, affects less than 200,000 people in the US population.
The risk of inheritance of defected gene is 1 in 10,000 in general population.
Research and statistical studies suggest that over 5% of the entire population carries the abnormal gene that is responsible for processing of Vitamin A. This also indicates that 5% of the entire population is susceptible to develop retinal diseases like retinitis pigmentosa and Stargardt's disease.
http://www.md-health.com/Stargardt'S-Disease.html
The risk of inheritance of defected gene is 1 in 10,000 in general population.
Research and statistical studies suggest that over 5% of the entire population carries the abnormal gene that is responsible for processing of Vitamin A. This also indicates that 5% of the entire population is susceptible to develop retinal diseases like retinitis pigmentosa and Stargardt's disease.
http://www.md-health.com/Stargardt'S-Disease.html